White House Chief of Staff Denis McDonoough earned raucous cheers from the left-wing activists gathered at J Street’s fifth annual conference in Washington, D.C. on Monday when he attacked Israel’s occupation of the West Bank. “An occupation that has lasted almost 50 years must end,” he said. J Street was founded to disrupt the close U.S.-Israel alliance and to serve as an alternative to the American Israel Public Affairs Committee (AIPAC), the powerful pro-Israel group.

McDonough also refused to back away from criticism of Israeli Prime Minister Benjamin Netanyahu for casting doubt on a Palestinian state: “we cannot pretend that Netanyahu’s comments were never made,” he said.

Earlier Monday, Netanyahu had apologized to Israeli Arabs for remarks he made last Tuesday, as Israeli voters headed to the polls, warning about high turnout among Arab voters. The Obama administration had funded programs to increase Arab turnout in the election.

Rabbi Jonathan Greenberg, reporting from the J Street conference, noted that the J Street crowd was considerably less enthusiastic about McDonough’s boilerplate commitment to support Israeli security and help it maintain its qualitative military advantage over neighboring states. Attendees were far more enthusiastic about McDonough’s reference to the fifth anniversary of Obamacare than they were to remarks about the administration’s support for Israel’s Iron Dome defenses.

Also addressing the J Street conference is former Secretary of State James A. Baker III, a foreign policy adviser to former Florida Governor Jeb Bush, who is preparing to run for president. J Street has grown under the protection of the Obama administration, which has used the group to push for its preferred policies in Congress, including opposition to further Iran sanctions.

Israel occupied the disputed West Bank in a defensive war in 1967, and has withdrawn from most Palestinian towns.